D3D11: Use clamp wrap mode for Integer textures. Until we can support all wrap modes for int textures, use a correct clamping scheme. This fixes several dEQP GLES3 FBO tests. This shuffles some of the tests in functional.texture.units since it hard-codes a different behaviour for all wrap modes, ignoring the sampler setting. BUG=angleproject:1244 TEST=dEQP-GLES3.functional.texture.* Change-Id: Ic7e89a111728dfb18821534996bf5b9a5ad172b6 Reviewed-on: https://chromium-review.googlesource.com/313997 Tryjob-Request: Jamie Madill <jmadill@chromium.org> Reviewed-by: Corentin Wallez <cwallez@chromium.org> Reviewed-by: Geoff Lang <geofflang@chromium.org> Tested-by: Jamie Madill <jmadill@chromium.org>